This invention belongs to the field of organic chemistry and the synthesis of cephalosporin antibiotics. The invention provides a superior method for removal of the methyl or ethyl ester group from cephalosporin and carbacephalosporin carboxylic acids. The process is economically important, because cephalosporin antibiotics are often processed in the form of an ester. The methyl and ethyl esters are convenient and economical to handle in chemical processing, however, such esters have been seldom used due to the difficulty in their removal. The ester group must eventually be removed, however, because the cephalosporins are used as pharmaceuticals in the acid or salt form.